Circuit interrupter



Dec. 17, 1946. p, BAKER 2,412,857

CIRCUIT INTERRUPTER Filed Jan. 9, 1943 4 SheetsSheet 1 ATTORN 1946- B. P. BAKER CIRCUIT INTERRUPTER Filed Jan. 9, 1943 4 Sheets-Sheet 2 WITNESSES: W.

INVENTOR fiery'ammPfiakefi ATTOR-N 'guishing structures and therefor.

r fatenied @ec. i7, g 1

Benjamin P. Baker,

to Westinghouse Pittsburgh, Pa., a

Turtle ill-cell, Pa assignor Electric Corporation, East corporation of Pennsylvania Application Januar 's, 1943, Serial No. 471,34?

19 Claims.

This invention relates to circuit interrupters in general and, more particularly, to are extinoperating mechanisms An object of my invention is to provide an improved circuit interrupter comprising a substantlally closed chamber and to position the stationary contact external to the chamber so that during the opening operation an arc may be drawn from the stationary contact through an aperture-in the wall. of the chamber into the interior of the chamber.

Another object is to provide an improved circuit interrupter of the type described in the immediately preceding paragraph and to provide means for putting the fluid disposed within the chamber under pressure to cause an election oi at least a part of the fluid out of the chamber and through the aperture to extinguish the arc.

Another object is to provide an improved circuit interrupter comprising substantially closed chamber andto dispose a plurality of relatively stationary contacts external to the chamber. I also provide a plurality of movable contacts cooperable with the stationaryv contacts to draw a plurality of serially related arcs through apertures disposed in the wall of the chamber. Preferably I put the fluid disposed in the chamber under pressure and cause its ejection out of the apertures to extinguish the serially related arcs.

Another object 'of my invention is to provide an improved circuit interrupter having improved piston means for facilitating circuit interruption. I associate a series coil with the piston meansjto assist the actuation of the piston means during the interruption of high currents.

Another object is to provide an improved circuit interrupter comprising a substantially closed chamber having a pair of stationary contacts dis posed externally of the chamber and substantially on opposite sides thereof. I provide suitably disposed apertures adjacent to the stationary contacts in the walls of the chamber through which a pair or movable contacts are actuated to draw a plurality of serially related arcs from the stationary contacts through the apertures and into the chamber. Preferably I dispose improved interrupting means adjacent to the apertures to facilitate the extinction of the serially related arcs.

Another object is to provide an improved circuit interrupter comprising a substantially closed chamber in which a plurality of serially related arcs are established. I contemplate establishing a pressure generating are within the chamber to put the fluid disposed therein under pressure and to thus cause the motion oithe fluid adiacent one or more or the serially related arcs to effect the extinction thereof. a

Another object is to provide an improved circuit interrupter of the type described in the immediately preceding paragraph in which means are provided for effecting the lateral movement of the pressure generating are so that the pressure generating arc will contact fresh fluid to increase the pressure formed within the chamher. I Another object is to provide an improved ciruit interrupter of the tym drawing a pressure generating arc and one or more series ing arcs. I provide an interrupting unit adjacent the pressure generating are which not only increases the gas generation of the pressure gencrating arc as compared to a plain break, but also adds interrupting ability to the entire circuit interrupter.

Further objects and advantages will readily become apparent upon a reading of the following specification taken in conjunction with the drawings, in which:

Figure 1 is an elevational view, partially in section, or a circuit interrupter embodying my in vention and shown in the closed circuit position;

Fig. 2 is an enlarged cross-sectional view taken substantially on the line iii-H of Fig. l and also shows the interrupter in the closed circuit position;

Fig. 3 is an enlarged fragmentary view taken on the line III-4H1 of Fig. 2 but showing the disposition of the contacts during a circuit opening operation;

Fig. 4 is a view in cross-section taken on the line IVIV of Fig. 3;

Fig. 5 shows a modification of my invention;

Fig. 6 is an enlarged elevational view in crosssection of an interrupter shown in the closed circuit position similar to Fig. 2 but a modification of my invention;

Fig. 7 is a fragmentary enlarged view in elevation, partially in section, taken on the line VIL-VII of Fig. 6;

Fig. 8 is an enlarged fragmentary view taken on the line VIII-VIII of Fig. 6 but showing the disposition of the contacts during a circuit openins operation; and

Figs. 9 through 26 show plan and sectional views in cross-section of plate details utilized in the interrupting units employed in the modification of my invention shown in Fig. 6.

Referring to the drawings interruptembodying and more particu- 'larly to Figure l,

3 the reference numeral l designates a tank filled to the level 2 with a suitable arc extinguishing fluid, in this instance oil. Clamped to the cover 3 of the tank I are two insulating bushings i. Depending from the lower ends of the insulating bushings ll are conducting brackets 5 which rigidly support in position two substantially closed chambers generally designated by the reference numeral e.

A conducting bridging member l arranged for vertical longitudinal reciprocating motion by means of an insulating lift rod s electrically connects the chambers '5 in the closed circuit position of the interrupter asshown in Fig. 1. Disconnect fingers 9 electrically engage the bridging member 7 as shown. Disposed externally of each chamber 6 are two insulating operating rods to biased downwardly by compression springs ii,

the latter being disposed between washers l2 rigidly secured to the rods it and fixed guides 63 rigidly secured to the chambers 6.

Operating levers is connected by the pins are to the rods l rotate torsion shafts i (see Fig. 2)

which actuate the movable contact structure disposed within the chambers 5. Electrostatic shields It are disposed at the lower ends of the chambers 6 to minimize corona formation.

Referring more particularly to Fig. 2, it will be noticed that the chamber 6 comprises a cylindrical insulating casing i'l having at its upper end an insulating cover plat is threadedly secured thereto. Levers is rigidly secured to the torsion shafts it are utilized to actuate the movable contacts 211. The movable contacts have rear guide portions 2!, the purpose for which will appear more clearly hereinafter.-

Stationary contacts 22, in this instance comprising segmental conducting members, are supported on annular conducting brackets 23 rigidly secured by screws to the cylindrical insulating casing 51. A helical tension spring 24 biases the segmental contacts 22 into engagement with the movable contacts 20 as shown.

Disposed on opposite sides of the cylindrical insulating casing I! from the stationary contacts 22, are insulating guide cylinders 25 having insulating cover caps 26. Disposed within the guide cylinders 25 are insulating guide spiders 21 which cooperate during the opening operation with the guide portions 2| to produce straight line movement of the movable contacts 211. Slots 28 disposed in the levers i9 cooperate with pins 29, the latter rigidly secured to the movable contacts 20, to cause the opening and closing motion of the movable contacts 20 in'response to rotation of the levers is as a result of rotation of th torsion shafts I5.

At the bottom end of the lower lever is is a movable contact 30 which cooperates with a sta-- tionary contact 3i to establish a pressure generating arc during the opening operation of the interrupter. A stud 32 electrically connects the stationary contact 3i to a connector 33 which is secured to the electrostatic shield IS. The disconnect fingers 9 in this instance are rigidly secured to the electrostaticshield M as shown. th electrostatic shield It being threadedly secured to the lower end of the casing l1 and closing the lower end thereof. Two vertically upstanding insulating lates 34, only one of which is shown in Fig. 2, provide means for preventing the pressure generating are established upon the separation of the movable contac'till from the stationary contact 3| from contacting the casing I1. and injuring the same.

asraesr At the upper end of the casing it I dispose piston means generally designated by the reference numeral 36. The piston means 35 comprises a cylindrical iron member 36 screwed into an aperture 36a formed in the cover plat la. The cylindrical iron member 36 has a lower flange portion 3'! which supports a guide cylinder -38 made of a non-magnetic material, in this instance brass. A serie coil 39 is disposed between the iron member at and the brass guide cylinder 36 and is electrically connected in series circuit by means of the connector it, the other end of which is electrically connected to the support bolt (ii which supports the conducting bracket 5 to the cover plate it.

Th other end of the series coil as is electri-- cally connected by means of the connector :32 to the stud bolt 33 which secures the annular con-' ducting bracket 23 to the casing i'i.

Operating within the brass guide cylinder 8%- is a piston armature as composed of a suitable magnetic material, in this instanc iron. Within the piston armature as is a valve 65 which is slightly biased to a closed p sition by'the compression spring 35m The'compression spring (46a exerts just enough upward biasing force to overcome the weight of th valve 65.

The upper end of the piston armature as is pivotally mounted by a pin it to a lever il, the latter being pivotally supported at its right hand end by a pin 8 to the bracket 59. A tension spring so biases the left-hand end of the lever er in a downward direction.

In this embodiment of my invention the insulating operating rods is are bridged at their upper ends by an insulating cross rod El which engages in the closed circuit position of the interrupter the lever d7.

In the closed circuit position of the interrupter the electrical circuit therethrough comprises the conducting bracket 5, support bolt 4|, connector M, series coll 39,connector t2, stud i bolt 43, annular conducting bracket 23, upper stationary contacts 22, upper movable contact 20, connector 53, intermediate movable contact 2d, intermediate stationary contacts 22, connector 5t, lower stationary contacts 22, lower movable contactszli, connector 55;, movable pressur generating contact 36. stationary pressure generating contact 3!, stud 32, connector 38. e ec- I trostatic shield 66, disconnect fingers 9, movable conducting bridging member I to the right-hand chamber 6 through which the circuit passes in atsismilar manner to the upper right-hand bracke When it is desired to open the electrical circuit through the interrupter shown in Fig. l the insulating lift rod 8 is actuated downwardly by suitable mechanism, not shown, to cause downward movement of the conducting bridging member 1. The conducting bridging member 1 slides downward in the disconnect fingers9, but maintaining electrical contact therewith. The

initial downward movement of the conductin bridging member 1 permits the compression springs ii to cause downward movement of the.

insulating operating rods Ill. The downward movement of the insulating operating rods Ill causes a counterclockwise rotation of the operating levers M as viewed in Fig. 2. The counter.- clockwise rotation of the levers II as viewed in Fig. 2 causes a counterclockwise rotation of the torsion shaft IE to result in counterclockwise rotation of the levers IS. The counterclockwise rotation of the levers 19 causes the simultaneous 4: formation or four serially related arcs associated extinction. vents 60 (see 4) be provided with each chamber a The are drawn between in the washer members the movable contact as and the'stationary con- Certain features or" the l tempting units tact 39 is a pressure generating are which puts are described and claimed and the there the ii-uid, in this instance oil, disposed within the 5 of given in my application filed May 153, i940, chamber 6, under pressure. The oilwithin the Serial No. 335,218, which issued December 8. i942 chamber c being under pressure assists in the as Patent 2,304,529 and which was assigned to interruption of the other. three serially related the assignee of this application.

arcs associated with the chamber '8. Following In place or the interrupting unit bl shown in the interruption of any one of the serially re- Fig. 3, an insulating nozzle 69 may be used, being lated arcs the circuit through the entire interthreadedly secured in the apertures 56 provided rupter is broken, and the further downward in the casing i"! as more clearly shown in 5. movement of the conducting bridging member? When this construction is usedthe arc Bl is breaks electrical engagement with the ringers 9 established centrally within the nozzle 69 and is and produces tw isolating gaps in the circuit, .15 subjected to anow oi fluid indicated by the one gap being in ed between each pair of disarrows in Fig. s. connect fingers 9 at the lower end of each cham- It will be apparent that the tension spring 59 her 8 and the movable conducting bridging mem- (see Fig. 2) may initially assist the compression her 1. Consequently, in the open circuit position springs Ii in biasing the operating meechanism of the interrupter all potential stress is removed to the open circuit position. During the interfrom the chambers 6. ruption of high short circuit currents the pres- V The interrupting means associated with each sure generated by the pressure generating arc pair of relatively movablecontacts will now be established between the contacts 30, 3| will cordescrlbed. Apertures 56 are formed in the side respondingly be high to produce a high pressure walls of the casing ll adjacent the stationary within the chamber to. This high pressure will contacts 22. Also disposed adjacent each stacause fluid to flow through the interrupting units my contact 22 is an interrupting unit, gen- 51 to extinguish the arcs drawn therein in the verally designated by the reference numeral 51 manner previously described.

and shown enlarged in Fig. 3. The interrupting During the interruption of low currents the unit or comprises a plurality of insulating pressure generated by the contacts 30, Si is corwasher members 58 (see Fig. 4) having relatively respondingly low, and supplementary means for large internal diameters. Alternately disposed raising the pressure within the chamber 8 is debetween the insulating washer members 58 are sirable. In this event the piston means assists insulating washer members 59 having relatively the pressure generating arc drawn between the small inner diameters as more clearly shown in 35 contacts 3, 535 to raise the pressure within the Fig. 4. The washer members 58, 59 are supchamber It will be apparent that upon downported by tie bolts Gil. The washer members ward movement or the insulating rods lo the 58, 55 when assembled on the tie bolts 80 provide cross rod Eli and the roller 62 will also move down a plurality of annular recesses 6| (see Fig. 3). to permit the tension spring to to force the lever An insulating bushing J32 is threadedly secured 41 in a counterclockwise direction bout the pivot in the aperture 55 and has a corrugated inner pin 48 to result in the piston armature being surface as as shown, The annular corrugations forced downwardly to compress the fluid within $3 in the bushing 62 cooperate with the annular the chamber t. Consequently the p ton armarecesses 6! provided by the washer members 58, Wm M assists Pressure generating a e d awn as to provide an interrupting unit 51 having an 45 w n he contacts 353. 35 to raise the pressure annularly corrugated inner surface within the chamber during the interruption of The inner insulating plate as (see Fig. 3 ha a low currents. This increase of pressure within guide portion 65 (see Fig. 2) which assists in the chamber facilitates the interruption of the guiding the movable contacts 20. The guide pora s Wi n the in rup in wills tions as are enlarged at so (see Fig. 3) to permit 50 t will be apparent that the series coil 39 will fluid flow from within the casing l1 through the move the piston armature l l downward. in any interrupting nit 51 n ut b twe the tamagnetic circuit composed of movable parts the tlonary contacts 22 as shown by the arrows in parts tend to move in a d rection adoring least Fig. 3. When the movable contact 20 separates reluctance o h m tic flux. Since the refrom the stationary contacts 22 during the open- 55 l ce f the pi n rm r x3 is relatively ing operation, an are a! is established which is mall a compared with the brass guide cylinder subjected to a longitudinal flow of fluid through the piston armature is will be moved down the interrupting unit 57 and out between the info the center or the series coil 39 to a point stationary contacts 22. When the instantaneous w r th rel ctan fer d t the ma n tic value of the current through the arc 61' decreases 0 x is a m m m- .21 its cyclic variation the longitudinal flow It Will n q en e apparent that I have through the interrupting unit 51 carries with it provided m ns r assistin the t sion spring the hot ionized gases and that portion of the oil 50 in operating the pist n m ans 35 du in hi h which has lost its dielectric strength as a resultshort circuit currents at a time when high presof its contact with the arc, so that as the current 65 sure within the chamber a is desirable to effect zero approaches, the last thread of conducting the interruption of the high current arcs G1 estabionized gas is surrounded by fresh clean turbulished between the stationary contacts 22 and the lent oil, which quickly transforms the entire arc movable contacts so. The assistance furnished path from one of. fair conductivity to one of good by the series coil 3i? will obviously decrease as the insulation. This fluid flow causes the dielectric current through the series coil 39 decreases. strength of the space within the interrupting Thu during the interruption. of small currents unit 51 to rise so rapidly that the recovery voltthe tension spring til may be relied upon to opage is unable to reestablish another half cycle crate the piston means it. However, during the oi arcing. To allow the gas to escape from the interruption of high short circuit currents the recesses of the interrupting unit following arc current through the series coil 39 will be increased the piston armature (i l.

- placing the oil in earnest and in this event both the tension spg Eit and the series coil 89 will cooperate to force the piston armature it downward to raise the pressure within the chamber d.

A further advantage of the coil 39 is that it exerts its force on the piston id immediately when the high current or short circuit is established. This speeds up the opening movement and exerts considerable pressure of the contacts on the oil. even before the pressure tong are between contacts to and iii is formed, or has reached sumcient length to become very effective. For high speed operation this feature is very important.

During the closing of the as will open to permit fluid, in this instance oil, to flow into the interior of the chamber t through provision of the valve to speeds up the closing operation, and also insures that fresh fluid will enter the chamber e through the top thereof during the closing operation. During the opening operation the valve to will, of course, remain closed. 7

It is thus apparent that any breaker operation at low current or at no current will cause the piston to and valve or to operate as a pump, circulating fluid in the top through the valve Q6 and out through the interrupters i, thus rethe casing ill, with fresh .oil from the larger. volume in tank i.

During the closing operation the insulating lift interrupter the valve rod 8 moves upward to raise the conducting bridging member l. The conducting bridging member '5 first electrically engages the disconnect ringers 9 and slides upward between them. Further upward movement of the conducting bridging member i raises the insulating operating rods it against the bias of both the compression springs H and the tension spring 5b. This upward movement of the insulating rods it rotates the operate ing levers it, the torsion shafts i5 and the levers is to result in contact being made between the movable contacts 20 and the stationary contacts 22 to efiect a closing of the circuit through the interrupter.

It will be obvious that I have positioned the stationary contacts 6. This has distinct advantages. The movable contacts to establish and draw the arcs W from the stationary contacts 22 through the apertures 58 and into the interior oi the chamber 8. By initiating the arcs 6? outside of the chamber t there is thus provided sumcient space for venting around the stationary contacts 22. Also this construction has the additional advantage of having the stationary contacts 22 exposed for ready inspection, adjustment and cooling.

In the embodiment of my invention shown in Fig. 6 the insulating casing ill has a metallic top cover plate to threadedly secured thereto. A cylindrical member ii composed of magnetic material, in this instance iron, is threadedly secured in an aperture Ha provided in the insulating bottom plate 19. A guide cylinder 12 composed of a suitable non-magnetic material; in this instance plate 12a, the latter being composed of a suitable magnetic material, in this instance iron. A piston armature 13 having a valve 16 disposed therein is biased downwardly by a compression spring 15. Disposed between the iron cylinder member II and the' brass guide cylinder 12 is a series coil 16 connected in series circuit. One end of the series coil 18 is connected by the connector II to the stud. bolt 18 which secures the disconnect brass, is supported by an annular 8 I fingers 9 to the ating bottom plate it. The other end ofthe series coil it is connected by the connector at to the stationary contact iii. A bolt iii electrically connects the metallic top cover plate it to a connector 82, the lower end of which is electrically connected to the upper conducting bracket 23.

Consequently, in the closed circuit position of the interrupter shown in Fig. 6 the electrical circuit therethrough comprises the conducting bracket 5, plate it, bolt Eli, connector 82, conducting brachet 23, stationary contacts 22, mov= able contact 2@, able contact 2d, intermediate stationary contacts 22, connector 56, lower stationary contacts 22, lower movable contacts 26, connector lib, movable contact to, stationary contact 8i, connector tit, series coil it, connector ll, stud bolt l8, disconnect fingers e to conducting bridging member i. The circuit then passes bridging member 8 to the other chamber t through which the circuit passes in an identical manner to the other line terminal not shown.

. Associated with the lower contacts 3i, so is an interrupting unit generally designated by the reierence numeral 88. The unit 83 comprises an end insulating plate 8 5, the configuration of which is more clearly shown in Fig. 7. Referring to Fig. '7, it will be insulating plate 85 has a cutout portion $5 to accommodate the movement of the movable contact so. Immediately adjacent to the end insulating plate 841 'is a pocket insulating plate 86 22 externally of the chamber which forms a plurality of pockets ti more clearly shown in Fig. 7. The pockets 81 retain a plentiful supply of fresh fluid ready to be acted upon by the pressure generating are established etweenthe contacts 30, 3!.

Immediately adjacent to the pocket insulatin plate 86 is a group of three insulating plates, the center one of which is herein called an insert insulating plate 88. The insert insulating plate 85 has a configuration, in this instance identical with the configuration of the end insulating plate 85. The insert insulating plate 88, however, has

a recess disposed therein to accommodate the insertion of an insert of magnetic material 89, in

this instance composed of iron and having a configuration more clearly shown in Fig. '7. On each side of the insert insulating plate 88 is a guard insulating plate 90 having a configuration identical to the and insulating plate 84. Tie bolts 9| rigidly secure the insulating plates into position, and they are supported in spaced relation above the insulating bottom plate 19 by a bracket 92 secured by screws 93 to the bottom insulating plate 1'9. The plates within the interrupting unit 83 may be repeated.

When the movable contact 30 is separated from the stationary contact 3| a pressure generating arc is established. The magnetic inserts 89 distort-themagnetic field about the pressure generating arc to cause it to move downward as indicated by the arrow 92a in Fig. 7 into the lower portion ill of the interrupting unit 83, where the pressure generating arc constantly contacts fresh fluid, in this instance oil, to generate increased gas and hence to greatly increase the pressure within the chamber 6.

By my providing the magnetic inserts 89 the connector as, intermediate movthrough the conducting observed that the end.

-issued June 13, 1993, to

has disposed at each The insulating that comparatively little lateral motion of the 7 pressure generating arc takes drawing of said arc past the stantly causes fresh liquid to engage the arc and hence to greatly increase the pressure within-the chambert and the interruptingability of the entire circuit interrupter.

Consequently, in this embodiment of my invenon, I have provided four eifective interrupters associated .with each chamber 0, the lower interrupter 83 not only affording an interrupting action but alsoconsiderably raising the pressure within the chamber 0 to effect fiuid flow through place, still the the threeinterrupting units 95 associated with the other three serially related arcs drawn during an opening operation of the interrupter.

General aspects of the interrupting unit 83 have been described and claimed in the following pat-.

ents, 1,899,605 which issued February 28, 1933, to Benjamin P. Baker and Ernest G. Kees; 1,911,072 which issued May 23, 1933, to Lloyd W. Dyer and Winthrop M. Leeds; 1,914,137 which Winthrop M. Leeds; 1,991,901 which issued February 19, 1935, to Winthrop M. Leeds; 2,039,054 which issued April 28, 1936, to Samuel H. Boden and Stanley T.

Schofield and 2,138,382 which issued November 29, 1938, to Winthrop M. Leeds and Ennio Ortensi, all of the foregoing patents being assigned to the assignee. of this application.

The interrupting units 95 will now be described with particular attention directed to Fig. 8. An insulating cyclindrical member 90 is threadedly secured in the apertures 50 provided in the casing I1. The insulating cylindrical member 96 end flange portions 91 which serve to compress and hold in rigid position a plurality of insulating plates which form the interrupting unit 95.

pockets 81 conatlases id charge plate 101, an orifice plate 503, an insulating inlet plate I04, and finally an end insulating plate 500 the configuration of which is more clearly shown in Figs. and 26. The insulating 99 and two end plate I08 has a central aperture cutout portions Q00.

Referring to Fig. 8 it will-be observed that upon assembling the several insulatingplates within P8858868 which to the region external to the chamber 8 and which are spaced at a plurality of spaced intermediate points along the passage means I01. The direcwith Figs. 1 and 2. A

At the inner end or the interrupting unit 95 is disposed an end insulating plate 98, the configuration of which is more clearl shown in Figs, 9 and 10. The insulating plate 98 has formed therein a. central aperture 99 and two cutout portions l00, the purpose for which will appear more clearly hereinafter.

Immediately. adjacent to the and insulating plate 98 is an insulating discharge plate IOI the configuration of which is more clearly shown in Figs. 11 and 12. The insulating discharge plate i0I hastwo discharge passages I02 and two outout portions I00. Immediately adjacent to the insulating discharge plate I 0| is an insulating orifice plate I 03, the configuration of which is more clearly shown in Figs. 13 and 14. The insulating orifice plate I03 has a central aperture 99 and four cutout portions I00.

Immediately adjacent to the orifice plate I 052 is an insulating inlet plate I04 the configuration of which is more clearly'shown in Figs. 15 and 16. inlet plate I04 has two entrance passages I05 and two cutout portions I00. Then follows an orifice plate I03, an insulating distion of the fluid discharge is shown by the arrows in Fig. 6. The direction of now of the fluidfrom the interior of the chamber 6 into the arcing passage means it? is indicated by the arrows in Fig. 8.

It will be obvious that the fluid entering the interrupting unit 95 through the inlet plates I00 may either exhaust directly between the stationary. contacts 22 or pass through the central aperture 99 in the orifice plates I03 to exhaust through the discharge passages I02 provided 1 the insulating discharge plates I 0|. I

General features of the interrupting unit are described and broadly claimed in an application entitled "Circuit interrupter filed Novem- 1942, Serial No. 465,244, now U. S. Patent Ludwig, Winthrop M. Leeds and Benjamin P. Baker and which was assigned to the assignee of this application.

The operating mechanism shown in Fig. 6 cperates in a manner identical to the operating mechanism previously described in connection further description thereof, consequently, seems pins E08 rigidly secured to the insulatingoperating rods I0 and the. torsion shafts I5, the speed of rotation of the levers 19 as a. function of the downward velocity of the conducting bridging member 1 may be varied. Obviously, by increasing the distance between the pins I08 and the torsion shafts ie, the rotation of the levers I9 and, consequently, the speed of operation of the contacts 20, 22 may be increased with respect to the downward velocity of the conducting bridging member l.' 1

I have provided small the chambers 0 to vents I09 at the top of permit any accumulated gas formed during an opening operation to escape but of the chamber 9. This helps to maintain the dielectric strength of the fluid within the chamber 8 at a high value. I

It will be observed that the series coil 10 will cause the actuation of the piston armature 13 upward to assist raising the pressure within the chamber 0 during the interruption of high short circuit currents. Thus during the interruption of high short circuit currents there is not only an increased pressure caused by the pressure generating are drawn between the contacts 30, 3|, but also the piston armature 13 is then actuated against the biasing action of the compression with the interior portions I00 also serve to provide discharge passages which lead unnecessary. It will be ob- I served that by varying the distance between the amass? a 11 spring it to further raise the pressure within .the chamber 6.

The rise in pressure within the chamber d is desirable during the interruption. oi high short circuit currents to eflect the necessary fluid fiow through the interrupting units 95 to efiect the extinction of the arcs bi drawn between the sta= tionary contacts 22 and the movable contacts it in Fig. 6.

It will be observed that when the current being interrupted is high the biasing action exerted by the inserts at. is greater and hence a greater volume of gaswill be formed at the pressure generating are drawn at the contacts 3t, iii to increase the pressure within the chamber 6. During the interruption of low currents the series coil to will not be as eflective as on the interruption of high short circuit currents to cause upward movement of the piston armature it.

Thus I have provided a means for utilizing the high short circuit currents to effect increased pressure within the chamber e during the intenruption of high short circuit currents.

When the piston armature it is actuated up.- wardly, the valve it remains closed. When the compression spring l5 returns the piston arma= ture it to its lower position the valve id opens to permit oil to flow into the chamber 6.

Although I have shown tour serially related breaks associated with each chamber 8, not counting the disconnect break, it is apparent that for a higher voltage-more breaks could be used.

Since the magnetomotive force of the series coils 39 in Fig, 2 and it in Fig. 6 isproportional tov the product of-the number of turns in the series coils and the electric current flowing through the series coils, it is readily apparent that by increasing the number of turns in the series coils 89, it the respective piston armatures til, it will be actuated at correspondingly lower current values. Consequently, by increasing the number of turns in the series coils, the pistons will be operativeat lower current values to increase thepressure within the chambers t. The number of turns in the series coils 39, it will then be determined by the operating conditions required.

It will, furthermore, be observed that in the operation of the interrupter shown in Fig. 2 it the pressure within the chamber 6 becomes very high during the interruption or high currents the piston means 35 may be held in its raised position, the insulating cross rod $2 meanwhile separating from the lever 41. In this event the tension spring ill will not assist the compression springs H to bias the operating mechanism to the open circuit position. v Also in this event it will be apparent that upon the subsidence of the pressure within the chamber 8 of Fig. 2 after interruption the piston means 35 will then be operative due to the tension in the tension spring 50 to flush contaminated fluid out through the apertures 58 in the casingi1. As mentioned previously, however, the turns in the series coil 39 may be increased to such an extent that the piston means 35 will be operative even during the existence of high pressure within the chamber 6 caused by the interruption of high currents.

It will be readily apparent that although I have shown my invention as applied to liquid type circuit interrupters, the some were merely for,

purposes of illustration and my invention is not limited to use only in liquid type circuit interrupters, but also may be used in connection w closed stationary chamber, a pair of stationary circuit interrupters used in gaseous mediums or even in air. If the circuit interrupters are operated in a gaseous medium, for instance air, the several insulating washers used in the interrupting units 57, the insulating plates used in the interrupting units 95 and the insulating plates used in the interrupting units 83 may all be composed of a suitable material which evolves a vapor upon being subjected to the action or an electric arc. Such a use of gas evolving material would facilitate the interruption of the arcs.

The term fluid as used herein and in the ap pended claims comprises liquids, vapors, gases and sprays.

Although I have shown and described specific embodiments of my invention, it is to be clearly understood that the some were merely for purposes of illustration, andthat changes and modifications may be made without departing from the spirit andvscope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, means defining a.

substantially closed stationary chamber, a plurality of relatively stationary contacts mounted external to the chamber so as to be freely vented,

a plurality of apertures in the wall of the chamher, a plurality of movable contacts movable away from the stationary contacts and through the apertures to withinthe chamber to draw a plurality of serially related arcs through the apertures, and means other than the arcs for putting the fluid within the chamber under pressure to cause an ejection of fluid out of the chamber and through the apertures substantially longitudinally of the arc to extinguish the arcs.

2. In a circuit interrupter, a substantially encontacts mounted substantially on opposite walls of the chamber so as to be freely vented, a pair of apertures through the walls of the chamber disposed adjacent to the two stationary contacts, a pair of cooperable moving contacts separable from the stationary contacts to draw two serially related arcs adjacent the two apertures, lever means for causing motion of the pair of moving contacts, means other than the arcs for putting fluid within the chamber under pressure to force the fluid out the apertures adjacent the arcs to M and the 'roller eflect the extinction of the same, and a torsion shaft for causing motion of the lever means.

3. In a circuit interrupter, a substantially enclosed chamber, a plurality of pairs of stationary contacts, an aperture through the wall of the chamber adjacent each contact, each pair of stationary contacts being mounted substantially on opposite sides of the chamber, a plurality of pairs of moving contacts to draw a plurality of arcs adjacent the apertures, a plurality of levers for causing the motion of the pairs of moving contacts, a plurality of torsion shafts for causing the motion of the levers, means for putting fluid disposed within the chamber under pressure to effect an ejection ofthe same out the apertures to exthe chamber under pressure to tionary closed chamber, a pair substantially on opposite sides apertures to draw across? eilect an election of the same out the apertures to extinguish the area-a lever for simultaneously causing the motion of. the pair of moving contacts, and means pivotally mounting the lever intermediate its ends.

5. In a circuit interrupter, a chamber, piston means for-putting the fluid within the chamber under pressure, spring means for urging the acturupter opening operation, and a series coil to assist the spring means during the opening operation.

6. in a circuit interrupter, a substantially staof relatively stationary contacts mounted externally of the chamher so as to he freely vented and substantially on op osite sides thereof,- a pair of apertures in the the pair of stationposed in one of-v the apertures, a pair orv movable contacts movable through the pair of apertures from within the chamber to engage the pair of stationary contacts in the closed circuit position of the interrupter, means fo simultaneously actuating the pair of movable contacts away from the pair of stationary contacts and through the pair of apertures to draw two serially relatedarcs through the apertures, and means other than the arcs for putting the fluid within the chamber unarcing surface of each interrupting unit having a plurality of recesses to forms corrugated arcin: surface, a pair or movable contacts cooperable with the pair of stationary contacts to draw two tures and into the der pressure to cause the election of the fiuidout of the chamber through the guish the arcs,

'l, in a circuit apertures to extininterrupter, a substantially closed chamber, a pair of stationary contacts mounted externally of the chamber and substantially on opposite sides thereoi, a pair of apertures in the wall of the chamber adiacent the pair oi stationary contacts, a pair of interrupting units disposedadjacent the pair of apertures, the arcing surface oi each interrupting unit having a plurality of recesses to form a corrugated arcing surface, a pair of movable contacts cooperable with the pair of stationary contacts to draw two serially related arcs through the pair of apertures and into the pair of interrupting units, and means for putting fluid within the chamber under pressure to cause the ejection of fluid through the pair of interrupting units and out the apertures to effect the extinction of the area.

8. In a circuit interrupter, a substantially closed chamber, a pair of relatively stationary contacts mounted externally or the chamber and thereof, a pair of apertures in the Wall of the chamber adjacent the pair of stationary contacts, at least one insulating nozzle disposed in one of the apertures, a pair of movable contacts movable through the pair of apertures to engage the pair tests in the closed circuit position of the interrupter, lever means for simultaneously actuating the pair of movable contacts away-from the pair of stationary contacts and through the pair of two serially related arcs through the apertures, and means for puttingthe fluid within the chambe under pressure to cause the ejection of the fluid out of the chamber through the apertures to extinguish the arcs.

9. In a circuit interrupter, a substantially closed chamber, a pair of stationary contacts mounted externally of the chamber and substantially on opposite sides thereof, a pair of aper-= tures in the wall of the chamber adjacent the pair of stationary contacts, a pair of interrupting units disposed adjacent the pair of apertures. the

of stationary conserially related arcs through the pair of aperver means for simultaneously actuating the pair of movable contacts, and means for putting fluid to cause the chamber under pressure to facilitate the extinction of the arcs, said last-mentioned means comprising relatively movable contacts separable to establish a pressure generating arc, and means affecting the magnetic field about the pressure it to move into engagement with fresh l quid to give increased pressure within the chamber.

11..In a circuit interrupter, two substantially closed chambers, rnovahlecontact structure dis-= posed, in each chamber, a plurality of torsion shafts extending through the walls of each chambar to operate the movable contact Structure dis= posed therein, arr-operating lever connected to each shaft, at least one operating rod for each chamber which is connected to the plurality of operating levers associated therewith? and a conducting bridging member operable to cause the formation of two disconnect gaps in the series circuit, the bridging member also causing the ho tuation of the operating rod associated with each chamber.

adjacent one end of the passage means, a cooperable movable contact movable through the arcing passage means chamber under pressure, and means for directing the fluid under pressure into the arcing passage means at a plurality of spaced points along the extinction of the arc. i

13. In a circut interrupter, a substantially closed chamber; a stationary contact mounted externally of the chamber, arcing passage means extending from the contact through the wall of the stationary contact heing dia arcing passage means to establish an arc therein, means for putting fluid disposed within the share her under pressure, and means for directing the fluid under pressure into the arcing means at a plurality of spaced points along the length of the arcing passage means to effect the extinction of the arc, and a plurality of discharge passages disposed at a plurality of spaces, inters mediate points along the length of the arcing passage means and communicating to the region exterior to the chamber.

14. In a circuit interrupter, a substantially closed chamber, a pair-oi stationary cents-lets mounted externally of the chamber and suhstantially on opposite sides thereof, a pair of movable contacts movable through the well of pair of interrupting units, le-

to establish an arc therein,

stationary contact t the chamber to engage the stationary contacts in the closed circuit position of the interrupter, an

-movable contacts movable through the walls of the chamber to engage the stationar contacts in the closed circuit position of the interrupter, an interrupting unit disposed adjacent each stationary contact through which the movable contact passes to establish an arc therein, lever means for simultaneously actuating the pair of movable contacts, means for putting fluid within the chamber under pressure, each interrupting unit utilizing the fluid under pressure to direct a plurality of jets toward the are established within the unit from spaced points along the arc, each interrupting unit also providing a plurality of dis:

charge passages iromspaced inte he: ate points along the arc which communicate to the region external to the chamber.

' 16. In a circuit interrupter, a chamber, means for putting fluid within the chamber under pressure, a stationary contact mounted externally of the chamber, a movable contact movable through a wall of the chamber to engage the stationary contact in the closed circuit position of the interrupter, an interrupting unit disposed adjacent the path of movement oi the movable contact, the movable contact being separable from the p to establish an are within the unit, the unit forming a plurality of entrance pas= sages through which the fluid under press asiaesr strikes the are at a plurality of spaced points along the arc, the unit also forming a plurality oi discharge passages spaced at intermediate points along the are which communicate with the region external to the chamber.

17. In a circuit interrupter, means for establishing a pressure generating arc and one or more assist in effecting extinction series interrupting arcs, means utilizing the pressure created by the pressure generating arc to ,assist in eflecting extinction of one or more of the interrupting arcs, and means for shooting lateral movement of the pressure generating arc to cause the latter to engage fresh fluid to generate increased pressure for effecting a more rapid inter ruption of the electrical circuit through the interrupter.

18. In a circuit interrupter, means for establishing a pressure generating arc and one or more series interrupting arcs, means utilizing the pres sure created by the pressure generating are to of one or more of the interrupting arcs, and magnetic means for efi'ecting lateral movement of the pressure gem erating are to cause the latter to engage fresh fluid to generate increased pressur for efiecting a more rapid interruption of the electrical circuit through the interrupter.

19. In a circuit interrupter, means for estab= lishing a pressure generating arc and one or more series interrupting arcs, means utilizing the preasure created by the pressure generating arc to assist in enacting extinction of one or more or the interrupting arcs, one or more fluid retaining pockets, means for lengthening the pressure gens erating are past one or more of the fluid retag the pressure generating arc will continue to engage, fresh fluid to generate in. creased pressure for effecting a more rapid inter= ruption of the electrical circuit through thein terrupter, and magnetic means cooperating with saidillast-mentioned means to move the arc lat. era y.

pockets so that 

